After violence, Arvind Kejriwal urges party workers to stay calm

New Delhi/Lucknow/Ahmedabad: Hours after Arvind Kejriwal was briefly detained at a police station in Gujarat, violence erupted in Delhi, Lucknow and Allahabad as workers from his party clashed with those from the BJP.  As the ugly scenes of violence played out on television, Mr Kejriwal in a late night press conference said, "We don't want to clash with the BJP. I request my workers not to get involved in this," adding, "For any role that our workers played in this evening's violence, I offer my apology." (Blog: On the road in Gujarat with Arvind Kejriwal)

Several people were injured in the riots and police used water cannons to disperse the crowds.

The street battles marred the announcement of national elections this morning. Hours after the dates were announced, Mr Kejriwal was stopped briefly by the police during the first day of his four-day tour of Gujarat. His supporters then gathered outside BJP offices in other cities to protest his detention.

The police used batons and water-cannons at the BJP's headquarters in the heart of Delhi.  Senior AAP leaders say stones and chairs were thrown at them from within the BJP complex. (See pics)

Moving through Kutch in the evening, Mr Kejriwal's car was attacked and its windshield broken. (Day 1 of Gujarat road-show, bumpy for Arvind Kejriwal)

Mr Kejriwal's Aam Aadmi Party or AAP says his harassment in Gujarat was ordered by the BJP's prime ministerial candidate, Narendra Modi, who has governed the state since 2001.

The BJP's Navin Kohli said that was in self-defence and that AAP initiated the violence. "These are urban Maoists," said the BJP's Prakash Javadekar.

Mr Kejriwal says his trip to Gujarat will allow him to verify claims of the extensive development of the state that has been highlighted by Mr Modi and the BJP in its election campaign..

Opinion polls favour Mr Modi and the BJP to emerge as the largest party, but say it will fall well short of a majority. (India's mammoth general election: factbox)

Mr Kejriwal, whose stunning breakthrough in the Delhi state elections in December highlighted public anger towards the political establishment, is taking on the major parties.